Internal combustion engine

ABSTRACT

A rotary internal combustion engine having a plurality of swinging arms spaced uniformly in a rotor housing and a rotor on a power output shaft adapted to engage the arms in said housing and thereby control the cycle of outward compression and exhaust strokes, and inward power strokes of each of said arms. Each arm includes an outwardly tapered, wedge-shaped horn member engageable within a recess provided in the adjacent engine housing to define an expandable compression chamber between said housing and each arm and to permit said arms to move freely between said inward and outward positions. In the preferred arrangement, the arms and rotor can shift laterally within the housing to positions of equilibrium, and the side portions of said arms and rotor include a plurality of labyrinth grooves in sealing relationship with respect to the rotor housing. Spherical combustion chambers in the housing adjacent the free end of each of said arms communicate with the interior of said housing and are adapted to direct an expanding charge of combustion gases against said arms and the exposed portion of the rotor. Said rotor and arms can be adapted to cause substantially complete combustion of the gas charges within the combustion chambers prior to expansion of the charges in said rotor housing. Exhaust ports provided in said housing selectively exhaust spent combustion gases from the interior of said housing, and a cam startup system is adapted to initiate the cycle of operation for the arms. The rotor may be adapted so that each arm will transmit a plurality of power impulses to the rotor for each complete rotor revolution, and further to overlap the power impulses of adjacent arms during the engine operation.

linited States Patent Hinckley [54] INTERNAL COMBUSTION ENGINE [72] Inventor: John N. Hinckley, Beloit, Wis. ['73] Assignee: Beloit College, Beloit, Wis.

[22] Filed: Sept. 24, i969 [2 l] Appl. No.: 870,331

Primary Examiner-Clarence R. Gordon Attorney-James P. Hume, Patrick H. l-lurne, Howard W. Clement, Wm. Marshall Lee, Henry L. Brinks, James M. Wetzel, Clyde F. Willian, Granger Cook, Jr., Richard G. Lione, Roy E. Hofer, Robert P. Cummins, James B. Blanchard, Robert L. Harmon, M. F. Jager, G. D. Hosier and D. A. Anderson 1451 MayQJWz [57] ABSTRACT A rotary internal combustion engine having a plurality of swinging arms spaced uniformly in a rotor housing and a rotor on a power output shaft adapted to engage the arms in said housing and thereby control the cycle of outward compression and exhaust strokes, and inward power strokes of each of said arms. Each arm includes an outwardlytapered, wedge-shaped horn member engageable within a recess provided in the adjacent engine housing to dene an expandable compression chamber between said housing and each arm and to permit said arms to move freely between said inward and outward positions. ln the preferred arrangement, the arms and rotor can shift laterally within the housing to positions of equilibrium, and the side portions of said arms and rotor include a plurality of labyrinth grooves in sealing relationship with respect to the rotor housing. Spherical combustion chambers in the housing adjacent the free end of each of said anns communicate with the interior of said housing and are adapted to direct an expanding charge of combustion gases against said arms and the exposed portion of the rotor. Said rotor and anns can be adapted to cause substantially complete combustion of the gas charges within the combustion chambers prior to expansion of the charges in said rotor housing. Exhaust ports provided in said housing selectively exhaust spent combustion gases from the interior of said housing, and a cam startup system is adapted to initiate the cycle of operation for the arms. The rotor may be adapted so that each arm will transmit a plurality of power impulses to the rotor for each complete rotor revolution, and further to overlap the power impulses of adjacent arms during the engine operation.

20 Claims, 2l Drawing Figures P'ATENTEDMM 9 |912 SHEET u1 nf 12 BY HUME, CLEMENT, HUME,

AND LEE PTNTEDMM 9 nmz SHEET u2 or 12n INVENTOR. JOHN N. HINCKLEY PATENTEDMM 9 m72 JOHN N. HINCKLEY BY HUME, CLEMENT, HUME,

AND LEE PATENTEDMAY 9 |972 SHEET nu nf 12 FIG. 8A

mvENToR JOHN N. HINCKLEY BY HUME,'CLEMENT, HuME,

AND LEE PATNTEUMM 9 is?? SHEU o5 0F v12 A O O 2 B O O INVENTOR.

JOHN N. HINCKLEY BY HUME, CLEMENT, HUME,

AND LEE PTNTEDMM 9mm 3,660,978

SHEET os or 12` 23| Flc-5,19

INVENTOR. JOHN N. HINCKLEY BY HUME, CLEMENT, HUME AND LEE ,DATENTEDMM 91972 3,660,978

SHEET n7nf12 INVENTOR.

JOHN N. HlNCKLEY BY HUME, CLEMENT, HUME,

AND LEE PATNTEDMM erm 3,560,978

snm new 12 INVENTOR. JOHN N. HINCKLEY BY HUME, CLEMENT, HUME AND LEE PATNTEDMM 9 |972 SHEET U9 UF 12 INVENTOR.

JOHN N. HINCKLEY BY HUME, CLEMENT, HUME,

AND LEE HEME 52 .Elm

PAT'N'TEDMM 9:9?2 3,860,978

SHEET 1o nr 12` I' INVENTOR. JOHN N. HINCKLEY BY HUME, CLEMENT, HUME,

AND LEE PATNTEDMM 9 |912 BY HUMEl CLEMENT, HUME,

AND LEE PATENTEUMM 9 1972 SHEET 12 nf 12- FIG. I8

AND LEE INTERNAL COMBUSTION ENGINE BACKGROUND AND GENERAL DESCRIPTION The present invention relates to an improved prime mover and more particularly relates to an improved rotary internal combustion engine which is capable of replacing conventional reciprocating piston engines.

As well known to those skilled in the art, the reciprocating internal combustion engines in current use have many inherent disadvantages. For instance, such engines have generally low thennal efficiency resulting mainly from the inability of the engine to fully utilize the energy in the fuel. Moreover, such engines generally have extremely poor pollutant emission characteristics,I since the fuel is not burned completely within the engine combustion and expansion chamber before it is exhausted to the atmosphere. The overall mechanical efficiency of reciprocating piston engines is also low, in the range of 25 percent, due to such factors as the ina bility of the pistons to produce power for the first 30 and last 40 of each stroke; the requirement of having two complete piston cycles to produce one power stroke in a four-cycle piston engine; and the need for power-absorbing static and dynamic counterbalancing and parasitic auxiliary systems.

Previous attempts to improve upon the thermal and mechanical characteristics of reciprocating piston engines have met with varying degrees of success. Reciprocating engine designs continue to require expensive fuels, continue to have unacceptable high pollution characteristics, and involve complicated structural arrangements which are expensive to manufacture, operate, and maintain, and which have unsatisfactorily low mechanical eiciency.

The present invention overcomes the above-mentioned problems incident to making and using reciprocating piston engines by providing an improved rotary internal combustion engine which is capable of operating with substantially improved mechanical and thermal efficiencies and which has greatly enhanced anti-pollution characteristics. Improved thermal efficiency and reduced pollutant emissions are possible because of the structural and functional characteristics of the rotary engine which permit more complete combustion of the air-fuel mixture during the operation ofthe engine. The invention also allows expansion of the combustion gases to a condition approaching atmospheric pressure, or about twice the volume possible in conventional piston engines. Similarly, the engine requires no crank case, and hence will create no crank case emissions. Improved mechanical efciency results from the structural and functional features of the present invention which cause the smooth and continuous flow of power to an output shaft, with a high horsepower to weight ratio. The engine also is capable of producing high torque at low speeds, and has a great flexibility of operation.

EXEMPLARY EMBODIMENTS Additional objects and features of the present invention will become apparent from the following description of severa] exemplary embodiments, wherein standard engine components, such as the carburetor, the throttling mechanism and the like, have been omitted for sake of clarity.

In the drawings:

FIG. l is a cross-sectional view of one embodiment of an internal combustion engine in accordance with the present invention which incorporates a single-lobe rotor and three swinging abutment arms;

FIG. 2 is a removed and enlarged sectional view of the combustion chamber incorporated in the engine illustrated in FIG. 1, showing a poppet valve means for sealing the associated combustion chambers and arms;

FIG. 3 is a removed and enlarged sectional view of the combustion chamber of the same engine, illustrating a modified labyrinth seal for'sealing the combustion chambers and arms;

FIG. 3A is a further enlarged sectional view of the labyrinth sealing between the associated arm and combustion chambers, as illustrated in FIG. 3;

FIG. 4 is a partial sectional end view of the engine illustrated in FIG. 1, schematically showing a cam start-up mechanism for initiating the movement of the swinging abutment arms;

FIG. 5 is a side view of the engine as viewed along the line 5-5 in FIG. l;

FIG. 6 is a removed perspective view of the sngle-lobe rotor incorporated in the embodiment of the engine illustrated in FIGS. l-5, particularly showing the labyrinth sealing means provided in the side portions thereof and the spline connection which pennits the rotor to be free-floating within the engine housing;

FIG. 7 is a removed perspective view of one of the swinging abutment arms incorporated in the engine embodiment illustrated in FIGS. 1-5, particularly showing the labyrinth sealing grooves incorporated on the sides thereof, and the spline connection which permits the arms to be free-floating within the engine housing;

FIG. 8A is a removed and enlarged top view of the labyrinth grooves incorporated on the side portions of the rotor and arms, as illustrated in FIGS. 6 and 7, showing the discontinuous and non-aligned arrangement of the grooves;

FIG. 8B is an enlarged and removed cross sectional view of the labyrinth sealing grooves showing in FIG. 8A, illustrating the depth ofthe grooves;

FIG. 9 is a partial sectional end view of an engine assembly formed from multiple engine units of the present invention which are joined to a common output shaft in a dynamically balanced relationship;

FIG. 10 is a sectional side elevational view of the multipleunit engine assembly as viewed along the line 10-10 in FIG.

FIG. ll is a sectional end view of a modified engine assembly incorporating dual engine units which are joined to a common drive shaft in a balanced relationship, with the charnbers ofthe engines cross-coupled;

FIG. l2 is a sectional side elevational view of the dual crosscoupled engine assembly as viewed along the line 12-12 in FIG. 1 l;

FIG. 13 is a partial sectional end view of an engine assembly in accordance with this invention which incorporates dual cross-coupled engine units wherein each of the engines includes a double-lobe rotor and four wedge-shaped swinging abutmentarms;

FIGS. 14A and 14B are joined sectional side elevational views of the engine assembly illustrated in FIG. 13, as viewed along the section lines 14A-14A and 14E-14B, respectively;

FIG. l5 is a partial sectional end view of the dual engine shown in FIGS. 13 and 14, illustrating a cam start-up mechanism for each engine unit in the dual engine assembly;

FIG. 16 is a partial sectional end view of a balanced single engine unit in accordance with this invention including a double-lobe rotor and six swinging abutment arms;

FIG. 17 is a sectional side elevational view of the single sixarm engine unit, as viewed along the line 17--17 in FIG. I6; and

FIG. 18 is a partial sectional end view of the engine unit shown in FIGS. 16 and 17, illustrating a cam start-up mechanism for the unit.

SINGLE LOBE ROTOR-SINGLE ENGINE UNIT FIGS. 1-8 illustrate a rotary internal combustion engine 100 constructed in accordance with this invention to incorporate three uniformly spaced swinging abutment arms A-C and a single-lobe rotor 150. The rotor is contained within the generally cylindrical opening defined by a rotor housing 120,

. and is mounted on a central drive shaft 130. The arms 140 and arms are directed sequentially inwardly against the rotor 150. The expanding air-fuel mixture thereby works against the exposed surface of the rotor 150 and against the arms 140AC to impart a rotational driving force to the rotor 150, and the rotor in turn transmits an output torque to the drive shaft 130.

As illustrated in FIG. 5, one end of the rotor housing 120 is closed by a flywheel housing 160, and the other end is closed by a fluid transfer housing 170. The housings 160 and 170 include centrally located main bearings 161 and 171, respectively, which support the shaft 130. Machined end plates 162 and 172, respectively, are defined by these housings 160 and 170 and seal the adjacent ends of the rotor housing 120. Suitable head bolts and gasketing material (not shown) are employed to assure that the plates 162 and 172 effectively seal the rotor housing 120. In addition, the end plates 162 and 172 provide support for pivot pins 141 (FIG. l) about which the abutment arms 140A-C swing during the operation of the engine 100.

As indicated in FIG. 7, one end of each of the arms l40A-C includes a splined aperture 142 for receiving corresponding splines (not shown) provided around the periphery of the pivot pins 141. The arms 140A-C are thereby fixed from rotation on the pivot pins 141, but are capable of floating or shifting laterally on the pins to maintain a position of equilibrium within the rotor housing 120 during the operation of the engine 100. As indicated in FIGS. 5 and 6, the rotor 150 also includes a splined aperture 151 which receives corresponding splines 131 provided on the shaft 130. Accordingly, the rotor 150 is also free-floating, and can float or shift laterally on the shaft 130 to a position of equilibrium within the housing 120.

The free-floating nature of the rotor 150 and the arms 140A-C permits effective sealing of the rotor and arms within the housing 120 by means of labyrinth sealing grooves 121 provided on the side portions of the arms 140 and rotor 150. As illustrated in FIGS. 8A and B, the labyrinth grooves 121 comprise short, discontinuous grooves provided in the side portion of the associated part in an unaligned orientation. Each groove 121 is arranged to follow the general profile of the associated arm or rotor and functions as a check valve to substantially stop the flow of gas past the arms or rotor in the slight clearance adjacent the end plates 162 and 172. The discontinuous nature and unaligned orientation of the grooves 121 also prevent gas from traveling laterally along the full length of the rotor or arm within the grooves during the operation of the engine 100. The slight clearance between the plates 162 and 172, rotor 150, and arms 140A-C is maintained substantially constant during the operation of the engine, regardless of engine load or operating temperature, by the freeoating connections for the arms and rotor, and by selecting the materials for the various parts to have substantially equal coefficients of expansion. Such labyrinth sealing eliminates the need for lubricating moving parts such as piston rings and seals.

As illustrated in FIG. 1, the free end of each of the swinging arms 140AC includes a bevelled contact surface 143 which allows the associated arm to engage with and seal against the rotor 150 along a flat and highly machined contact surface. During the power stroke of the engine 100, the contact surface 143 is urged against the periphery of the rotor 150 by the force of the charge expanding against the associated arm. The arm contact surface 143 prevents any substantial leakage between the arms 140 and the rotor 150 during these power strokes, and also allows the rotor and arms to withstand high loading forces by distributing the loads over a large area.

The inner surface 144 of each of the arms 140A-C is also machined to provide a smooth contact surface for engaging with the rotor 150 to return the arms outwardly after the inward power stroke is completed. An inward projection 146 is also formed on each arm 140A-C to define the point closest to the associated pivot pin 141 at which the rotor 150 will engage the arm. Further, the inner surface of each arm 140A-C includes a relief portion 147 to allow the rotor 150 to engage with the projection 146. This arrangement assures that the arms 140A-C and the rotor 150 will contact at a point remote from the pivot pin 141, so that the arms engage with the rotor 150 at a point of substantial leverage. The rotor housing 120 is further provided with a plurality of sealing strips 148 adjacent each of the arms 140A-C. The strips 148 engage with the swinging arms l40A-C and separate the compression, cornbustion, expansion and exhaust chambers of the engine from each other, as explained in more detail hereinafter,

As shown in FIG. l, the end of each ann 140AC adjacent the pivot pins 141 defines a sliding valve portion 145. The valve portion 145 swings in close association with the end plates 162 and 172 during the swinging of the associated arm 140, and thereby functions to selectively open and close an adjacent exhaust port lA-C provided in the end plates. As illustrated by the positions of the arms 140B and C in FIG. l, the exhaust ports 190A-C are arranged in the end plates 162 and 172 to be closed by the adjacent valving portion 145 when the associated arm is in its outermost position. Similarly, as illustrated by the position of the arm 140A in FIG. 1, the ports 190A-C are arranged so that the adjacent valving portion 145 opens the port completely when the associated arm swings into its innermost position against the periphery of the rotor 150. The burned combustion gases are exhausted from the engine through a suitable exhaust manifold system (not shown) which is connected directly to these exhaust ports 190. In the preferred embodiment, as illustrated in FIGS. 1 and 7, each valve portion 145 has a recess 145A which eliminates unnecessary weight.

To accommodate the valve portions 14S, the rotor housing includes a plurality of conforming recesses 159 which are adapted to receive the valve portions as the associated arm 140 swings inwardly toward the rotor 150. The abovedescribed sealing strips 148 are positioned to prevent the ex haust gases from becoming trapped within these recesses 159, and thereby avoid a back pressure which would retard the movement of the arms 140. If desired, the danger 0f back pressure in these recesses 159 can be avoided by venting the recesses to the atmosphere.

In accordance with this invention, each of the arms 140A-C in the engine 100 is provided with an outwardly projecting hom member 180. The horns are formed integrally with the associated arm 140, and are designed to extend outwardly from the ann for a distance which exceeds the length of the inward arm stroke. Further, the horns 180 are positioned adjacent the free end of each of the arms 140A-C, and terminate in an arcuate front edge 181 which is positioned to be substantially concentric with the pivot pin 141 of the associated arm 140A-C. Each horn 180 further includes a rear edge 182 which is arranged to converge with the front edge 181 to provide the horn with an outwardly tapered or wedge-shaped configuration. As seen in FIG. 1, the front edges 181 of the horns 180 are spaced from the bevelled portion 143 on the free end of the associated arm 140A-C. The free end of each arm 140A-C can thus dene a substantially flat contact surface 149 which is adapted to receive the force of the expanding combustion gases during the operation of the engine 100.

As shown in FIG. 1, the rotor housing 120 is formed with a plurality of horn recesses 122 which accommodate the projecting horns 180 on each of the arms 140A-C. These recesses 122 have a shape which closely conforms to the shape of the horns 180 and, as illustrated by the position of the arms 140 B and C, will receive the adjacent horn when the associated arm is in its outermost position. Similarly, as illustrated by the arm 140A in FIG. 1, the recesses 122 have a selected depth which allows the horn 180 to be free of the recess as the associated arm 140 moves to its innermost position. Further, the recesses 122 include arcuate forward edges 123 which, like the from edge 181 of the horns 180, are concentric with the arm pivot pin 141. The horn edge 181 will therefore slide in sealed engagement with the associated recess edge 123 as the arm 140 moves inwardly during the operation of the engine. Since the extent of the horns 180 exceeds the length of the inward stroke of the anns 140, the horns will remain in sealed engagement with the rotor housing 120, along the edge 123, throughout the operation of the engine. Thus, the horn recess 122 and the adjoining space behind each of the arms 140A-C defines a closed compression chamber 124 which expands in volume as the associated arm moves inwardly toward the rotor 150. In accordance with this invention, these expandable compression chambers 124, formed behind each arm 140A-C, function to compress a charge of air-fuel mixture to a desired pressure before the charge is transferred to a separate combustion chamber. The outwardly tapered shape of the horns 180, and the arrangement of the horns in the recesses 122, prevent the development of a partial vacuum within the horn recess or compression chamber which would otherwise present a drag on the swinging arms 140 and inhibit the operation of the engine 100.

The engine 100 in accordance with this invention is also provided with a plurality of combustion chambers 125, each having its own ignition spark plug 126. As illustrated in FIG. 1, the combustion chambers 125A-C are uniformly spaced in the rotor housing 120 so that one combustion chamber is positioned outwardly from the free end of each of the arms 1140 A-C. The combustion chambers 125A-C are spherical in configuration to provide the chambers with a very low surface-tovolume ratio which aids complete combustion of the air-fuel charge. As indicated in FIGS. 1-3, an outlet channel 127 is provided in the rotor housing 120 to bring each of the combustion chambers 125A-C into fluid communication with the interior of the rotor housing 120 at a point outside of the contact surface 149 on the free end of the adjacent arm 140A-C. Hence, the expansion force of the air-fuel charge resulting from ignition of the charge in the combustion chamber 125 will be directed inwardly toward the free end of the adjacent arm 140 A-C and the rotor 150 by channels 127. Accordingly, a substantial torque force will be transmitted to the rotor 150 by the expansion of the charge against the adjacent arm 140A-C and also directly against the rotor. As seen in FIGS. 1 and 2, a sealing strip 148 is provided adjacent the outlet channels 127 to seal the compression chambers 124 from the adjacent expansion chamber in the interior of the rotor housing 120.

Further, the contact surface 149 on each arm 140A-C is provided with means to seal the outlet channels 127 when the associated arm 140 is in its outermost position, with the horn 180 seated within the horn recess 122. With an effective seal in the channel 127, the air-fuel charge can be ignited in the combustion chamber 125, and combustion of the charge completed before the channel 127 is opened by the ann 140. As illustrated in FIG. 2, this sealing may be accomplished by a fixed poppet valve 128 which seats and seals against the mouth of the inlet channel 127. The poppet valve 128 and the associated channel 127 are preferably inclined so that the axes of the valve and channel are substantially coincident and so that the valve 128 follows an arc which is concentric with the pivot pin 141 as the associated arm 140 swings outwardly. By this arrangement, the poppet valve 128 can be accurately seated in the mouth of the channel 127, and an effective seal is accomplished. In the alternative, the combustion chambers 125A-C can be sealed with labyrinth sealing means, as shown in FIGS. 3 and 3A. To accomplish this labyrinth seal, the mouth of the outlet channel 127 is provided with a plurality of labyrinth grooves 129A, and the mating portion of the arm contact surface 149 is provided with a plurality of offset labyrinth grooves 129B. The grooves 129A and 129B cooperate to effectively seal the joint between the arm surface 149 and the outlet channel 127 when the arm 140 is in its outermost position.

As indicated in FIGS. 1 and 5, the rotor housing 120 is also provided with a plurality of unifomily spaced inlet and transfer valve assemblies 200A-C. The valves 200 are generally cylindrical in shape, and are arranged outside of each of the arms 140A-C so as to be in fluid communication with the adjacent compression chamber 124. As shown in FIG. 5, an intake passage 132 and manifold 133 connect each of the valve assemblies 200 to a suitable carburetor system (not shown) which feeds the engine with metered charges of a combustible air-fuel mixture. The intake passage 132 terminates in an annular ring 134 which is aligned with an inlet ring 136 in the valve assembly 200.

The engine 100 in accordance with this invention also includes means to transfer a compressed charge of lair-fuel mixture from each ofthe compression chambers 124 through the apertures 202 and into combustion chamber adjacent the preceding arm 140. To accomplish this transfer function, the transfer housing 170 includes a fluid-tight transfer passage A connecting the valve assembly 200A to the combustion chamber 125C adjacent the preceding arm 140C. As shown in FIG. 1, a similar transfer passage 135B connects the valve assembly 200B to the combustion chamber 125A, adjacent the preceding arm A; and a passage 135C connects the valve assembly 200C to the combustion chamber 125B of the arm 140B. This arrangement permits the charges of air-fuel mixture to be compressed first in one of the compression chambers 124 and then transferred directly into one of the separate combustion chambers 125A-C in the compressed state. The passages 135 terminate in valve sockets 137 in communication with the combustion chambers 125. A suitable poppet valve 138 is provided in these sockets and is biased closed by a suitable compression spring or the like (not shown). The force of the expanding gases upon the ignition of the air-fuel mixture in the combustion chamber 125 also tends to keep the valves 13B closed. The valves 138 will open in response tothe pressure of the compressed air-fuel charge, and permit the transfer of the compressed charge from the compression chambers 124 into the connected combustion chamber 125.

As shown generally in FIGS. l and 5, the transfer valve assemblies 200 are removably mounted within the housing 120 by suitable means such as threads or the like (not shown). In the preferred arrangement, the entire valve assembly 200 can be readily removed from the housing 120 for inspection, repair or replacement. As indicated in FIGS. l and 5, the intake ring 136 places the interior of the assembly 200 in fluid communication with the adjacent manifold openings 134 and 136. Similarly, a series of compression ports 208 places the interior of the valve 200 in fluid communication with the transfer channels 135A-C.

Each valve assembly 200 also includes a sliding valve sleeve 214 that is dimensioned to slide within the valve assembly and which includes a hub that receives the stem of a poppet valve 220. As indicated in FIG. 5, the sleeve 214 is machined to seat against the inner end of the valve assembly 200 to close the compression ports 208. A calibrated compression spring 221 constantly urges the sleeve 214 inwardly into such a closed position. The spring 221 assures that the ports 208 leading to the transfer channels 135 are normally closed by the sleeve 214, but permits the sleeve to be retracted to open the ports 208. The poppet valves 220 of the valve assemblies 200 seat against the inner end of the sleeve 214, to selectively close the sleeve.

The outer end of each valve assembly 200 is closed by a housing 204. A compression spring 227 in the housing 204 biases the poppet valve 220 outwardly into seating relationship with the sleeve 214. A conventional rocker arm assembly 230 is provided to actuate the poppet valve 220. As wellknown to those skilled in the art, the rocker arm assembly 230 includes a rocker arm 231 which is actuated by suitable cam means 232 on the shaft 130 and a lift rod 233. The arm 231 operates to bear against the stem of the valve 220 and overcome the closing force of the spring 227.

In operation, each of the transfer valve assemblies 200 is normally in a closed position, such as illustrated in FIG. 5. ln this normal position, the poppet valve 220 is closed against the sleeve 214. Further, the spring 221 forces the sleeve 214 to close the compression ports 208. The rocker arm assembly 230 is timed to lift the poppet valve 220 into an open position when the associated arm 140 begins to swing inwardly. A charge of air-fuel mixture is thereby pulled from the engine carburetor (not shown) through the intake manifold openings 134 and 136 and into the associated compression chamber 124. The rocker arm` assembly 250 is also timed to release the valve 220 and allow the spring 227 to seat the valve against the sleeve 214 when the associated arm 140 reverses direction and begins to move outwardly.

After the compression chamber 124 of the associated arm 140A-C is filled with the charge of air-fuel mixture, the outward movement of the arm will compress the charge. The compression spring 227 is calibrated so that when the compressed charge reaches a selected pressure the charge overcomes the force of the spring 227 so that further outward movement of the arm 140 will slide the valve 220 and sleeve 214 outwardly into an open position to expose the compression ports 208. The valve assembly 200 then connects the compression chamber 124 to the transfer passage 135A-C. Continued outward movement of the associated arm 140A-C will then transfer the compressed air-fuel charge from the compression chamber 124 to the connected combustion chamber 125A-C. The compressed charge then can be ignited by the plug 126 to impart a torque force to the rotor 150.

As seen from FIGS. l and 6, the sloping portion 155 on the periphery of the rotor 150 leads the inwardly moving arms 140A-C to a low dwell segment 156. The low dwell segment 156 is concentric to the axis of rotation of the rotor 150 and extends along the rotor surface for a selected number of degrees. The dwell segment 156 thereby stops the inward movement of the arms 140A-C and defines the limit for inward arm travel. The next segment of the rotor 150 is a rise segment 157, designed to force the engaged arm 140A-C outwardly from its innermost position (e.g., arm 140A in FIG. 1) toward its outermost position (e.g., arm 140C, FIG. 1). This rise segment 157 is shaped to force the arms 140A-C outwardly with approximately simple harmonic motion as the rotor 150 rotates through a selected number of degrees.

The remaining portion of the rotor 150, between the rise segment 157 and the high point 153, comprises a high dwell segment 158. This segment 158, like the low dwell segment 156, is concentric with the axis of rotation of the rotor 150, and will therefore function to maintain the engaged arm 140A-C in its outermost position as the rotor 150 rotates through a selected number of degrees (e.g., arm 140C, FIG. l). The rotor 150 is thereby provided with a periphery having a single lobe, terminating at the high point 153, which allows each of the arms 140AC to complete its operating cycle as the rotor 150 rotates through 360. By this arrangement, the expansion of a charge against each arm l40A-C and against the exposed portions of the rotor 150 will transmit one power impulse or stroke to the rotor 150 per rotor revolution. Further, since the three arms 140A-C are spaced by 120, the cycle of operation for the arms will be uniformly spaced 120 out-of-phase.

In accordance with this invention, the rotor fall segment 154 is designed to complete the inward movement of the engaged arm 140A-C as the rotor rotates for less than 120, for instance l 10. This arrangement will allow the inwardly moving arms to dccelerate smoothly, and assures that the inward power stroke of one arm, such as the arm 140A, is complete before its exhaust port 190A-C is opened by the inward movement ofthe adjacent following arm, such as 140B. Further, the valving portions 145 of the arms 140A-C and the associated exhaust ports 190A-C are arranged so that the air-fuel charge expanded against one arm, such as the arm 140A in FIG. l, is not exhausted from the rotor housing 120 until the following arm, such as arm 140B, moves inwardly through a small arc, such as 10 or 20. Hence, the exhaust ports 190A-C will not open prematurely, and optimum torque on the rotor 150 is ob tained by overlapping of the power impulses of the arms 140A-C.

The overlapping of the power impulses on the rotor 150 is further facilitated by arranging the low dwell segment 156 of the rotor to contact each of the arms 140A-C for from about 10 to 20 of rotor rotation after the inward stroke of the following arm has started. The dwell segment 156 thereby precludes outward movement of the engaged preceding arm, such as arm 140A in FIG. l, until after the power strokes of the adjacent arms, such as arms 140A and B in FlG. 1, have overlapped. This arrangement of the dwell segment 156 also allows the charge to expand fully against the inwardly moving arm 140 (e.g., arm 140A) and the rotor 150 before the inward movement of the following arm (e.g., 140B) opens the associated exhaust port 190. The rise segment 157 on the rotor will then drive the preceding arm (e.g., 140A) outwardly and thereby force the spent exhaust gases into the exhaust system through the ports 190.

Further in accordance with this invention, the operation of the engine is timed so that a compressed air-fuel charge is ignited in the combustion chambers A-C before the nose 153 of the rotor has rotated beyond the associated arm A-C, respectively. More particularly, the engine 100 is adapted so that the high dwell segment 158 of the rotor 150 will engage with the associated arm l40A-C and maintain the channels 127 closed for 45 to 60 of rotor rotation during the combustion of the compressed air-fuel charge in the associated combustion chamber 125A-C. In other words, the dwell segment 158 is designed to maintain the channels 127 closed for a period of between approximately 35 and 50 percent of the degrees of rotation through which the rotor engages each of the three uniformly spaced arms 140. This arrangement ofthe rotor 150, the arms 140A-C, and the spherical combustion chambers 125A-C allows complete combustion of the compressed air-fuel charge to occur in the combustion chambers, before the gas is expanded into the rotor housing 120. Such complete combustion of the air-fuel charge substantially reduces the exhaust emissions and air pollutants resulting from the operation of the engine 100.

The internal combustion engine 100 is also provided with start-up and counterbalancing systems. ln this connection, the flywheel housing 160 contains a flywheel 163 keyed to the drive shaft 130. The flywheel 163 includes counterweights to offset the mass of the single-lobe rotor 150 so' that the rotor and flywheel are in static and dynamic balance during operation ofthe engine. An accessory drive gear 164 and pinion 165 are also provided in the housing 160 for driving engine accessories, such as lubricating pumps and magnetos (not shown). A removable cover plate 166 permits inspection and repair of the components of the housing 160.

The flywheel housing 160 further includes a cam start-up mechanism to provide the swinging arms 140A-C with positive drive during the initial cranking of the engine 100. To provide this start-up mechanism, the arm pivot pins 141 are extended into the flywheel housing 160 (FIG. 5) and a cam lever 167 is fixed to each of the pins by suitable keys or the like. Further, each of the cam levers 167 is arranged to extend in a generally tangential direction with respect to the flywheel 163 and has a cam follower roller 168 at its free end (FIG. 4). Due to this arrangement, a force applied to the rollers 168 will pivot the levers 167 and cause corresponding rotational movement ofthe connected pin 141 and arm 140A-C.

The engine 100 also includes means for positively driving the cam rollers 168, the levers 167 and the connected arms 140A-C during engine start-up. The flywheel 163 thus defines an interior cam track 169 which is arranged in a predetermined relationship with respect to the rotor 150 so as to sequentially engage with the cam rollers 168 as the flywheel 163 rotates. The cam track 169 will thereby drive the arms 140A-C sequentially inward into engagement with the fall segment 154 on the rotor 150, and the resulting arm movement will draw an initial air-fuel charge into the associated compression chamber 124. The cam track 169 then releases the rollers 168 and permits the rotor 150 to return the arms 140A-C outwardly. As described above, this outward arm movement will compress the airfuel charge in the associated chamber 124 and will then transfer the compressed charge through the connected valve assembly 200 into the connection combustion chamber 125A-C.

As shown in FIG. 4, the periphery of the cam track 169 includes a cam lift portion 169A adapted to engage with the followers 168 after the nose 153 on the rotor 150 has traveled past the free end of the associated arm 140AC. The portion 169A will thereby move the arms 140A-C sequentially inward against the fall segment 154 on the rotor 150 with approximately simple hannonic motion. Further, the cam track 169 includes a low dwell portion 169B which engages with the cam followers 168 and permits the associated arms 140AC to remain inwardly against the low dwell segment 156 on the rotor 150 for a predetermined time period. A release portion 169C of the track 169 follows the low dwell portion 169B and leads to a high dwell portion 169D. These track portions 169C and 169D release the rollers 168 and allow the rotor 150 to force the arms 140AC sequentially outward into the position as indicated by the arm 140C in FIG. 1. The arms 140 will thereby compress the charge of air-fuel mixture which was drawn into the associated compression chamber 124 by the previous inward arm stroke. The high dwell portion 169D of the track 169 is arranged to be adjacent the rollers 168 when the high dwell segment 158 of the rotor 150 is engaged with the associated arm 140A-C.

Further, the track 169 is arranged so that it is spaced from the cam follower roller 168 by a small distance, in the range of 0.01 to 0.025 inches, during normal engine operation. Thus, the track 169 engages with the rollers 168 to provide positive drive to the associated arms 140A-C only during engine startup or during any engine misfire, and permits the rotor 150 to operate without interference thereafter.

In the operation of the engine 100, the swinging abutment arms 140AC transmit a torque force to the rotor 150 in proportion to the magnitude of the force imposed upon the arms and the exposed portion of the rotor by the combustion of the charge. The rotor 150 and arms 140A-C function to compress the air-fuel charges and then transfer the compressed charges to separate spherical combustion chambers, where complete combustion can take place before the charges are expanded. Further, the rotor and the arms seal the expanding charge in one segment of the engine 100 from the spent charge exhausting from another engine segment.

The interrelationship between the components of the engine 100 will be apparent from a description of the operation of the engine through one complete cycle. Since the engine 100 consists of three symmetrical segments, each including' one of the arms 140A-C, the engine cycle could begin with any one arm. For purposes of illustration, the engine operation will be described with reference to a cycle initiated by the movement ofthe arm 140A.

To start the engine 100, the flywheel 163 is cranked, in a clockwise direction as seen in FIGS. 1 and 4, by applying an energizing force to a conventional starting bendix drive or the like (not shown). As indicated in FIGS. 4 and 5, the rotational movement of the flywheel 163 will cause the portions 169AD of the track 169 to sequentially engage with the cam rollers 168. The cam track 169 thereby operates, through the rollers 168 and the associated levers 167, to sequentially drive the arms 140A-C inwardly against the rotor 150. Further, the track 169 and the rotor 150 are arranged with respect to the rocker arm assemblies 230 (FIG. 5) so that such initial inward movement of the arms 140A-C is timed to coincide with the opening of the poppet valve 220 on the` associated transfer valve 200A-C.

By this arrangement, the initial inward stroke of the arms 140AC will draw a charge of air-fuel mixture through the associated transfer valve assemblies 200A-C and into the adjacent compression chambers 124. Then, when the rollers 168 engage with the release portion 169C of the cam track 169, the rotation of the rotor 150 will force the arms outwardly and thereby compress the air-fuel charge in the compression chambers 124. When the charges in the chambers 124 reach a predetermined pressure, the transfer valve assembly 200 will shift from the closed position to an open position. Thereafter, the outward arm movement of the associated 140A-C will transfer the compressed air-fuel charge through the valve assembly 200 and the connected transfer passage 135 into the connected combustion chamber 125AC (see FIG. l). After the combustion chambers 125A-C are sequentially fed with an initial charge of compressed air-fuel mixture in the abovedescribed manner, the air-fuel charges are ignited by the plugs 126, and the charges expand and drive the associated arms 140A-C inwardly against the rotor 150. After the engine 100 is started, the cam track 169 will not engage with the associated rollers 160 as the flywheel 163 rotates, unless there is a mistire of one of the engine segments.

Furthermore, the engine is timed so that the compressed air-fuel charges are ignited in the combustion chambers A-C while the associated arm 140AC remains closed across the outlet channel 127, as illustrated generally in FIG. 2 and 3. ln accordance with this invention, the arm 140 continues to be held in this outward position by the rotor 150, closed across the channel 127, as the rotor rotates an additional 45 to 60 after ignition. The air-fuel charge hence will be completely burned within the spherical combustion chambers 125A-C before it is expanded in the rotor housing 120. Then, as indicated by the position of the arm A in FIG. l, the rotor 150 releases the arm 140 and permits the charge to expand against the ann and the periphery of the rotor.

As the charge continues to expand from one combustion chamber, such as from the chamber 125A, a second compressed charge is ignited in the following combustion chamber, such as in the chamber 125B. Next, as the continued rotation of the rotor 150 brings the rotor nose 153 beyond the end of the following arm, such as ann 140B, the ann is released and will be driven inwardly against the fall segment 154 of the rotor 150 by the expansion force of the second charge. The power impulses transmitted to the rotor 150 by the expansion of the gases from the adjacent combustion chambers 125A and 125B are thereby overlapped in time, and the torque forces on the rotor 150 are smooth and continuous.

The overlapping of the power impulses on the rotorV 150 is also facilitated by the arrangement of the exhaust ports 190 and the associated sliding valve portions on the arms l40A-C. As seen in FIG. ll, the ports 190 are positioned so that they remain closed by the valve portions 145 during the initial 10 to 20 of inward movement of the associated arm l40A-C.

Hence, the gas charge expanding against the ann 140A, for instance, will not start to exhaust from the rotor housing 120 through the port 190B until a second gas charge starts to expand against the following adjacent ann 140B; the next arm engaged by the rotor 150. After the port 190B opens, the continued motion of the adjacent arms 140A and 140B and the rotor will scavenge the spent combustion gases from the rotor housing 120 and force such gases out through the opened exhaust port B.

The cycle of operation for the arms 140B and 140C is the same as for the arm 140A, and the operations of the adjacent arms l40B-C and ll40C-A overlap in the same manner as described above with respect to the adjacent arms 140A and B. Since the compression, combustion and expansion chambers of the engine 100 are separated, the design of the rotor 150 and arms 140 can be adjusted to provide the engine with the desired characteristics, such as expansion of the charge to approximately atmospheric pressure before the charges are exhausted to the surrounding atmosphere.

Some of the characteristics of the engine in accordance with this invention will be evident from a computerized simulation of the operation of an engine 100 having a 7 #inch internal diameter for the rotor housing 120 and a 4 inch width for the rotor 150 and arms 140A-C. Such a simulated engine had the following characteristics:

l. Compression Chamber Volume-approx. 30 cu. in.

2. Expansion Chamber Volume-approx. 54 cu. in.

3. Combustion Chamber Volume-approx. 3.12 cu. in.

4. Effective Expansion Ratio-approx. l2 to l Based on 100 percent air charts, and an estimated ratio of specific heats (K) of 1.34, the projected indicated horsepower for the simulated engine is approximately 50.31 HP, at 1,200 RPM. The indicated torque is approximately 1,641 inch pounds or 137 foot pounds. The Brake Horsepower would be approximately 45 BHP, at 1,200 RPM, with an estimated 90 percent mechanical efficiency.

MULTIPLE UNIT ENGINE ASSEMBLY FIGS. 9 and 10 illustrate a modified rotary internal combustion engine assembly 300 in accordance with this invention. The engine assembly 300 is formed from multiple engine units 300A and 300B which are joined together around a common drive shaft 330. Each of the illustrated engine units 300A and B is identical in construction to the above-described engine unit 100, and incorporates three uniformly spaced abutment arms 140A-C and a single-lobe rotor 150. Modified transfer housings 370 permit the separate units 300A and B to be joined rigidly together along the shaft 330. The other components of the engine units 300A and B also have been given the same reference numerals as the common component in the engine 100.

As indicated in FIG. l0, the units 300A and B are joined on the shaft 330 so that the rotors and arms of the units are in static and dynamic balance. The need for any massive counterbalancing means for the assembly 300 is thereby eliminated. Since the illustrated engine assembly 300 comprises two units 300A and B, the rotors 150 in the units are fixed to the common shaft 330 so as to be 180 out-of-phase. Further, the rotor housings 120 for the units 300A and B are arranged so that the swinging arms l40A-C for the unit 300A (shown in solid lines in FIG. 9) are oriented 60 out-of-phase with the corresponding arms 140A-C on the other engine unit 300B (as shown in broken lines in FIG. 9). The engine units 300A and B are thereby arranged in static and dynamic balance.

During the operation of the assembly 300, each engine unit 300A and B operates in the same manner as the abovedescribed engine 100. However, due to the out-of-phase orientation of the plurality of arms 140A-C on the units 300A and 300B, the arms will operate to transmit a power impulse to the common shaft 320 for each 60 of revolution of the shaft. The assembly 300 hence can be controlled by common ignition and throttling means to function as the equivalent of a conventional 12 cylinder, four-cycle piston engine, with six power impulses to the rotors 150 per shaft revolution. Furthermore, it is apparent from the above description that the assembly 300 can be formed from a selected even or odd number of engine units which are joined in a balanced fashion along the common shaft 320. The assembly 300 in accordance with this invention thus has great flexibility and can be adapted to suit the horsepower, power impulse-frequency, and space requirements of a variety of special industrial applications.

MULTIPLE UNIT ENGINE ASSEMBLY- CROSS- COUPLED FIGS. l1 and 12 illustrate an additional modified engine assembly 400 in accordance with this invention. The assembly 400 comprises dual engine units 400A and B which are joined to a common drive shaft 430 in cross-coupled relationship. Each of the units 400A and B is similar in construction to the above-described engine 100 and, hence, the common components have been indicated by the same reference numerals. Modified transfer housings 470A and B are adapted to rigidly secure the units 400A and B together and to crosscouple the compression and combustion chambers of the two units.

The single-lobe rotors 450A and B included in the engine units 400A and B, respectively, have the same construction as the above-described rotor 150. As indicated in FIG. 12, these rotors 450A and B are joined to the common shaft 430 in an axially aligned relationship. The engine flywheels 163 offset the mass of these aligned rotors 450A and B and maintain the engine assembly 400 in static and dynamic balance during operation. This alignment for the rotors 450A and B permits the cross-coupled engine units 400A and B to operate in the proper sequence.

Each of the engine units 400A and B also includes three swinging abutment arms 440A-C and 440D-F, respectively, which are uniformly positioned around the shaft 430. The construction of each of these arms 440A-F is similar to the construction of the above-described arms A-C incorporated in the engine 100, and like portions have been given the same reference numerals. The unit 400A is positioned on the shaft 430 so that the arms 440A-C (shown in solid lines in FIG. 1l) are 60 out-of-phase with the arms 440D-F of the unit 400B (shown in broken in FIG. 1l). This arrangement places the combustion chambers 125AC and 125D-F of the engine units 400A and B, respectively, in axial alignment with the valve assemblies 200A-F and the connected compression chambers 124 of the opposite engine unit. In addition, the modified transfer housings 470A and B, as shown in FIG. l2, define fluid-tight transfer passages 435 between these aligned combustion and compression chambers. Hence, the compression chambers 124 in each engine unit 400A and B are in direct fluid communication with the combustion chambers 125 in the opposite unit through short and substantially straight fluid passages which minimize internal fluid losses in the engine assembly 400. The short transfer passages 435 will further reduce the travel time and the velocity of the air-fuel charges during the transfer of the charges from the compression chambers 124 to the combustion chambers 125.

In operation, the engine assembly 400 is started by cranking the flywheels 163 in the conventional manner so that the cam tracks 169 engage with the cam rollers 168. As described above with respect to the engine 100, the tracks 169 will positively drive the arms 440A-F sequentially inward and thereby draw charges of air-fuel mixture into the associated compression chambers 124 through the intake channels 132. The continued rotation of the rotors 450A and B induced by the inertia of the flywheels 163 will then force the arms 440A-F sequentially outward and compress the air-fuel charges.

After a selected gas pressure is reached in the compression chambers 124, further outward movement of the arms 440A-C will open the valve assemblies 200A-F and transfer the compressed air-fuel charges into the connected combustion chambers 125 through the direct transfer passages 435. More specifically, the charge compressed in the chamber 124 adjacent to arm 440A is transferred to the combustion chamber 125D adjacent the arm 440D; the charge compressed by the arm 440B is transferred to the combustion chamber 125E adjacent the arm 440E; and the charge compressed by the arm 440C is transferred to the combustion chamber 125F adjacent the arm 440F. Thus, the charges of air-fuel mixture compressed by the arms 440A-C of the engine unit 400A are transferred for ignition and expansion into the combustion chambers 125 of the other engine unit 400B. The compression chambers 124 in the engine unit 400B are similarly connected by the transfer channels 435 to the axially aligned combustion chambers 125A-C in the opposite unit 400A. Specifically, the charge compressed by the arm 440D is transferred to the combustion chamber 125C associated with the arm 440C; the charge compressed by the arm 440E is transferred to the chamber 125A adjacent the arm 440A; and the charge compressed by the arm 440F is transferred to the combustion chamber 125B adjacent the arm 440B.

After the transfer of the compressed charges occurs in the above-described manner, the charges are sequentially ignited in the combustion chambers 125 by the spark plugs 126. The charges will then expand sequentially against the associated arms 440A-F and rotors 450A or B and thereby transmit a substantial torque force to the output shaft 430. As described above with respect to the engine 100, the rotors 450A and B, the arms 440A-F and the exhaust ports are arranged to overlap the expansion of the charges against the rotor and thc adjacent arms (for instance, the arms 440A and B in the unit 400A and the arms 440D and E in the unit 400B), so that the flow of torque to the shaft 430 is smooth and continuous.

Furthermore, as described above with respect to the engine 100, the assembly 400 is timed so that the combustion chambers 125 remain closed by the associated arm for an additional 45 to 60 of rotor rotation (i.e.: about 35-50 percent of the engagement of the rotor with each arm) after the air-fuel charges are ignited by the spark plugs 126. This arrangement permits substantially complete combustion of the air-fuel charges in the spherical combustion chambers 125 before the charges are released for expansion into the rotor housing 120, and thereby substantially reduces the pollutant emissions of the assembly 400. The fully expanded charges are then exhausted from the rotor housing 120 through the exhaust ports 190 in the same manner as described above with respect to the `engine 100.

MULTIPLE UNIT ENGINE ASSEMBLY-DOUBLE LOBE ROTORS FIGS. 13 and 14 illustrate a rotary internal combustion engine assembly 500 constructed in accordance with this invention. The assembly 500 is formed from dual engine units 500A and B which are substantially identical in construction and are cross-coupled together about a common shaft 530. In accordance with this invention, the individual engine units 500A and B include double lobe rotors 550A and B, respectively, which are arranged in axial alignment on the common shaft 530. Furthermore, the units 500A and B each include four uniformly spaced swinging abutment arms 540A-D and 540E-H, respectively.

Referring to FIGS. 13 and 14 in more detail, the section 14A-14A in FIG. 13 is a section taken in the engine unit 500A, and the section 14H-14B is a section taken in the unit 500B. Both such sections are illustrated in FIG. 14. Each of the engine units 500A and B includes a rotor housing 520 which surrounds the central shaft 530 and provides a generally cylindrical chamber for the associated rotor 550A or B. As shown in P IG. 14, the housings 520 are machined to have substantially the'same width as the swinging arms 540 and the r0- tors 550. The ends of the engine assembly 500 are closed by flywheel housings 560 and 570. Suitable bearings 571 support the common shaft 530 centrally disposed in these housings. The housings 560 and 570 define machined end plates 562 and 572, respectively, which seal the adjacent ends of the engine assembly 500. The assembly 500 also includes a central transfer housing 575 which is mounted on the shaft 530 so as to seal the interior of the engine units 500A and B from each other. The housing 575 defines machined face plates 576. These housings 560, 570 and 575 include apertures for receiving suitable head bolts and gasketing material (not shown) to join the housings together in sealed relationship and for supporting the pivot pins 541 (FIG. 13) of the swinging abutment arms 540A-H.

As shown in FIGS. 14 and l5, the housings 560 and 570 incorporate flywheels 563 for cranking the engine assembly 500. Further, a cam track 569 is provided on the flywheels 563 for engaging with cam follower rollers 568. As described above with respect to the engine 100, the rollers 568 are joined to the adjacent arms 540A-H by levers 567A-H, respectively. The cam tracks 569 will operate through the levers 567 and rollers 568 to sequentially drive the arms 540A-H inwardly when the flywheels 563 are cranked.

More specifically, as seen in FIG. l5, the cam track 569 on each flywheel 563 includes a pair of diametrically opposed cam lift portions 569A which lift the rollers 568 and drive the connected arms 540 inwardly against the associated rotor 550. A pair of diametrically opposed first dwell portions 569B on each track 569 follow the lift portions 569A and engage the rollers 568 to allow the arms 540 to remain inward for a selected time period. A pair of opposed release portions 569C on the tracks S69 then release the rollers 568 so that the rotors 550 can drive the associated arms 540 outwardly. Finally, a pair of opposed second dwell portions 569D on the tracks 569 allow the arms 540 to remain in an outward position for a selected time period.

As further described with respect to the engine 100, the cam tracks 569 are arranged to clear the rollers $68 during the normal operation of the engine assembly 500, and to engage with the rollers 560 during engine start-up or misfire. The arm movement induced by the tracks S69 will hence draw in an initial charge of air-fuel mixture into the compression chambers of the assembly 500.

As indicated in FIGS. 13 and 14, the rotors 550A and B are connected to the common shaft 530 by keys, and the arms 540A-H are similarly mounted on the pivot pins 541. This arrangement mounts the arms 540A-H and the rotors 550 within the rotor housings 520 in a free floating relationship, so that the rotors and arms can shift laterally within the housings during the operation of the assembly 500. The free-floating rotors 550 and arms 540 can hence be sealed against the plates 562, 572 and 576 by means of labyrinth sealing grooves 521 provided on the side portions of the arms and the rotors.

As described above with reference to FIGS. 8A and 8B, the labyrinth grooves 521 are short and discontinuous, and are arranged in an unaligned orientation which follows the general profile of the associated arm or rotor. Each of the labyrinth grooves 521 thus functions as a check valve to substantially stop the flow of gas past the arms or rotors adjacent the plates 562, 572 and 576 of the assembly 500. The effectiveness of the seal created by the grooves 521 is enhanced by selecting the materials for the rotors, arms, and housings to have substantially equal coefficients of expansion. The clearance between the rotor, arms and end plates described above will hence be substantially constant regardless of the load or operating temperature of the engine assembly 500.

The swinging abutment arms 540A-I-I are identical in construction. As illustrated in solid lines in FIG. 13, four of the arms l540A--D are uniformly spaced in the engine unit 500A around the associated rotor 550A. As shown by the broken lines in FIG. 13, the other four arms 540E-H are unifonnly spaced about the rotor 550B within the engine unit 500B. Further, the engine units 500A and B are offset on the shaft 530 so that the four arms 500A-D are 45 out-of-phase with the other four arms 540E-H. As also illustrated in FIG. 13, the rotors 550A and B are joined to the shaft 530 in an axially aligned relationship. Such orientation for the rotors 550 and arms 540 permits the engine units 500A and B to operate jointly in the assembly 500 to produce a smooth and continuous application of torque to the output shaft 530.

The free end of each of the swinging arms 540A-I-I includes a bevelled contact surface 543 for engaging with and sealing against the periphery of the associated rotor 550 during the inward power stroke of the arm. Further, each arm 540 includes a machined inner surface 544 adapted for engaging with the periphery of the associated rotor 550 as the rotor returns the arm outwardly after the power stroke is completed. A projection 546 on each arm defines the point closest to the associated pivot pin 541 at which the associated rotor 550 will engage the arms. A relief portion 547 on each arm allows the rotors 550 to engage with the projections 546. The projection 546 thereby causes the rotor 550 to contact the arms at a point of substantial leverage which is remote from the pivot pins 541. Suitable sealing strips (not shown) may be provided on the arms 540 to seal the compression, combustion and expansion chambers of each engine units 500A and B from each other.

ln accordance with this invention, each of the anns 540A-H has front and rear-edges 581 and 582, respectively, which converge to provide each arm with an integral projecting horn member 580 which extends outwardly from the arm. The front edge 581 of each arm is arcuate and generally concentric with the associated pivot pin 541 and extends outwardly for a length exceeding the predetermined distance of the inward arm stroke. The front edge 581 is also spaced, as indicated in 

1. A rotary internal combustion engine comprising: a housing defining a generally cylindrical rotor chamber having substantially parallel end walls; a rotor rotatably mounted within the rotor chamber on an output shaft and having a substantial transverse surface and further having side portions spaced adjacent said end walls; a plurality of swinging arms pivotally mounted around the periphery of said housing and spaced uniformly with respect to said rotor, with each of said arms having side portions spaced adjacent said end walls and a free arm end adapted to engage with said rotor surface; said rotor surface including a first segment sequentially engageable with the free end of each of said arms to permit said arms to move to an inward position with respect to said rotor and a second segment sequentially engageable with the free arm ends to return each of said arms to an outward position expand said housing as said rotor continues to rotate; a combustion chamber defined in said housing adjacent the free end of each of said arms in fluid communication with said rotor chamber and adapted to be closed by the adjacent free arm end when the adjacent arm is in its outward position, and further adapted to permit a charge of combustion gases to expand inwardly into said rotor housing against the adjacent arm end and the exposed portion of said rotor to thereby transmit a power impulse to said rotor and shaft; exhaust means in fluid communication with said rotor chamber and arranged so that outward movement of said arms and the continued rotation of said rotor force spent charges of combustion gases from the rotor chamber through said exhaust means; means sealing said side portions of said rotor and said arms with respect to said housing end walls; an outwardly tapered horn member provided on each of said arms adjacent the free ends thereof and projecting outwardly into a generally conforming recess provided in the adjacent housing portion, each of said horn members having outwardly converging edges with one edge being positioned to slide in sealing engagement with said housing as said arms move between said inward and outward positions, said tapered horns and housing defining single expandable compression chambers, which are sealed from said rotor housing by said horn members, with said tapered configuration of said horns preventing the formation of sealed pockets which induce the creation of an engine-retarding partial vacuum forces within said housing recesses; valve means in fluid communication with each compression chamber and arranged to open and thereby pull charges of air-fuel mixture sequentially into said compression chambers as the associated arms move inwardly against said rotor and further arranged to close and thereby seal said compression chambers and sequentially compress the charges of air-fuel mixture as the associated arms are driven outwardly by said rotor; means for selectively transferring charges of compressed airfuel mixture from each compression chamber to the combustion chamber associated with the following arm; and start-up means for initiating the cycle of operation for said engine.
 2. A rotary engine in accordance with claim 1 wherein said combustion chambers are spherical in configuration to provide said chambers with a low surface-to-volume ratio and further wherein said rotor surface includes a high dwell portion defined between said first and second rotor segments and adapted to sequentially engage the free ends of said arms and maintain the associated combustion chambers closed by the adjacent arms after ignition of combustible charges in said combustion chambers for a period of between approximately 35 percent and 50 percent of the degrees of rotation through which said rotor engages each arm, so that substantially complete combustion of said charges occurs in said combustion chambers before said rotor releases said free arm ends and permits the charges to expand into said rotor chamber.
 3. A rotary engine in accordance with claim 2 wherein said housing includes a plurality of recessed valve seats in communication with said combustion chambers and wherein the free end of each of said arms includes an outwardly projecting valve head for engaging with and sealing against the adjacent valve seat as said high dwell portion of said rotor maintains said arms in said outward position, so that said valve seat and head cooperate to seal said combustion chambers during the combustion of charges of gas in said chambers.
 4. The rotary engine in accordance with claim 2 wherein said free end of each of said arms and the inner portions of said housing adjacent said combustion chambers include a plurality of labyrinth grooves which cooperate to seal the combustion chambers from said rotor chamber when said high dwell segment of said rotor maintains said arms in said outward positions against said housing.
 5. A rotary internal combustion engine in accordance with claim 1 wherein said arms and rotor are adapted to move transversely within said rotor housing to a condition of equilibrium between said end walls and further wherein said means sealing said rotor and arms with respect to said end walls comprises a plurality of discontinuous labyrinth grooves provided in an unaligned arrangement in the side portions of said arms and said arm horn members and in the side portions of said rotor, so as to follow the general contour of the associated arm and rotor and function to prevent the flow of combustion gases past said arms and rotor.
 6. A rotary internal combustion engine in accordance with claim 1 wherein said exhaust means comprises an exhaust port provided in said housing adjacent each of said arms and a mating valving portion provided on said adjacent arms, with each of said ports being arranged to be closed by said adjacent valving portion when the associated arm is in said outward position and to open into fluid communication with said rotor chamber when said adjacent arm is moved to said inward position.
 7. A rotary combustion engine in accordance with claim 6 wherein said exhaust ports are arranged to be opened into fluid communication with the rotor chamber by the mating valving portion when the associated arm has engaged said first portion of said rotor and has swung inwardly through a selected degree of rotor rotation so that the exhaust of combustion charges from said rotor chamber through said ports starts after torque has been transmitted to said rotor by the expansion of a gas charge against the arm associated with the open port, to thereby assure that the torque forces on said rotor are overlapping.
 8. A rotary engine in accordance with claim 1 wherein said first and second segments of said rotor surface are adapted to engage with the free ends of said arms and more said arms inwardly and outwardly, respectively, with substantially simple harmonic motion.
 9. A rotary internal combustion engine comprising: a housing defining a generally cylindrical rotor chamber having substantially parallel end walls; a rotor rotatably mounted within the rotor chamber having a substantial transverse surface and further having side portions spaced adjacent said end walls; a plurality of swinging arms pivotally mounted around the inner periphery of said housing and spaced uniformly with respect to said rotor, with each of said arms having side portions spaced adjacent said end walls and a free arm end adapted for engaging the surface of said rotor; said rotor surface including a first segment sequentially engageable with the free ends of said arms to permit the force of expanding combustion gases to drive said arms to an inward position against said rotor, a second rotor segment sequentially engageable with the free arm ends to return said arms to an outward position adjacent said rotor housing, and high and low segments between said first and second segments to releasably retain said arms in said outward and inward positions, respectively, for a selected degree of rotor rotation; an outwardly tapered horn member provided on each of said arms adjacent the free ends thereof having outwardly converging edges and projecting outwardly into a generally conforming arm recess provided in the adjacent housing portion, with one of said horn edges being positioned to slide in sealing engagement with said housing within said adjacent recess as said arm moves between said inward and outward positions; said tapered arm horns and housing defining single expandable compression chambers, which are sealed from said rotor housing by said horn members, with said tapered configuration of said horns preventing the formation of sealed pockets which induce the creation of an engine-retarding partial vacuum forces within said recesses; means sealing said side portions of said rotor and arms with respect to said end walls; a spherical combustiOn chamber defined in said housing adjacent the free end of each of said arms in fluid communication with said rotor chamber; valve means in fluid communication with each compression chamber and arranged to open and thereby pull charges of air-fuel mixture sequentially into said compression chambers as the associated arms move inwardly against said rotor and further arranged to close and thereby seal said compression chambers and sequentially compress the charges of air-fuel mixture as the associated arms are driven outwardly by said rotor; means for selectively transferring charges of compressed air-fuel mixture from each compression chamber to the combustion chamber associated with the following arm; means to seal said combustion chambers from said rotor chamber when the free end of the adjacent arm is in said outermost position; said high dwell segment of said rotor being adapted to maintain said free ends of said arms in said outward position sealing said combustion chambers after ignition of said charges in said combustion chambers for from approximately 35 percent to 50 percent of the degrees of rotary rotation through which said rotor engages each of said arms; a plurality of exhaust ports provided in said housing adjacent said arms; and exhaust valving portions provided on said arms adjacent said ports adapted to close said ports when the associated arms are in said outward position and further adapted to open said ports and permit gases to exhaust from said rotor chamber when the associated arm has moved toward said inward position for a selected degree of rotor rotation.
 10. A rotary internal combustion engine comprising: a housing defining a generally cylindrical rotor chamber having substantially parallel end walls; a rotor rotatably mounted within the rotor chamber on an output shaft and having a substantial transverse surface and further having side portions spaced adjacent said end walls; a plurality of swinging arms pivotally mounted around the periphery of said housing and spaced uniformly with respect to said rotor, with each of said arms having side portions spaced adjacent said end walls and a free arm end adapted to engage with said rotor surface; said rotor surface including a first segment sequentially engageable with the free end of each of said arms to permit said arms to move to an inward position with respect to said rotor and a second segment sequentially engageable with the free arm ends to return each of said arms to an outward position adjacent said housing as said rotor continues to rotate; a combustion chamber defined in said housing adjacent the free end of each of said arms in fluid communication with said rotor chamber and adapted to be closed by the adjacent free arm end when the adjacent arm is in its outward position, and further adapted to permit a charge of combustion gases to expand inwardly into said rotor housing against the adjacent arm end and the exposed portions of said rotor to thereby transmit a power impulse to said rotor and shaft; exhaust means in fluid communication with said rotor chamber and arranged so that outward movement of said arms and the continued rotation of said rotor force spent charges of combustion gases from the rotor chamber through said exhaust means; means sealing said side portions of said rotor and said arms with respect to said housing end walls; an outwardly tapered horn member provided on each of said arms adjacent the free ends thereof and projecting outwardly into a generally conforming recess provided in the adjacent housing portion, each of said horn members having outwardly converging edges with one edge being positioned to slide in sealing engagement with said housing as said arms move between said inward and outward positions, so that said tapered horns prevent the creation of an engine-retarding partial vacuum force within said housing recesses, and further permit said recesses and swinging arms to define eXpandable compression chambers which are sealed from said rotor housing by said horn members; means for selectively transferring charges of compressed air-fuel mixture from each compression chamber to the combustion chamber associated with the following arm; start-up means for initiating the cycle of operation for said engine, said start up means comprising; flywheel means secured to said output shaft and defining a circular cam track around said shaft adapted for rotation with said rotor; a cam follower connected to each of said arms and arranged so that said followers are spaced uniformly around said shaft adjacent said cam track; said track including a lift segment engageable with each of said followers to drive the connected arm inwardly against said first rotor segment to expand the associated combustion chamber and permit a charge of air-fuel mixture to be drawn into said expanding chamber; said cam track further including a release segment positioned to guide said cam followers so that said connected arm can be driven outwardly by said second rotor segment to thereby compress the air-fuel charge in the associated compression chamber; and cranking means for rotating said flywheel and said rotor to rotate said cam track segments sequentially into engagement with the cam followers on each of said arms and thereby initiate the first cycle of operation for each of said arms and said engine.
 11. A rotary internal combustion engine comprising: a housing defining a generally cylindrical rotor chamber having end walls; a double-lobe rotor rotatably mounted within the rotor chamber on an output shaft and having a substantial transverse surface and further having side portions spaced adjacent said end walls; six swinging arms pivotally mounted around the periphery of said housing and spaced uniformly with respect to said rotor, with each of said arms having side portions spaced adjacent said end walls and a free arm end adapted to engage with said rotor surface; said rotor surface defining a pair of first rotor segment adapted to sequentially engage with the free arm ends of a pair of opposed arms and permit said engaged arms to move to an inward position with respect to said rotor and thereby transmit a torque force to said rotor and shaft; each rotor further including a pair of second rotor segments sequentially engageable with the free ends of a pair of opposed arms to return said engaged pair of arms to an outward position adjacent said housing; an outwardly tapered horn member provided on each of said arms adjacent the free end thereof and projecting outwardly into a generally conforming recess provided in the adjacent housing portion, each of said horn members having outwardly converging edges with one edge positioned to slide in sealing engagement with said housing as said arms move between said inward and outward positions, said tapered horns and housing defining single expandable compression chambers, which are sealed from said rotor housing by said horn members, with said tapered configuration of said horns preventing the formation of sealed pockets which induce the creation of an engine-retarding partial vacuum forces within said housing recesses; valve means in fluid communication with each compression chamber and arranged to open and thereby pull charges of air-fuel mixture sequentially into said compression chambers as the associated arms move inwardly against said rotor and further arranged to close and thereby seal said compression chambers and sequentially compress the charges of air-fuel mixture as the associated arms are driven outwardly by said rotor; a combustion chamber defined in said housing adjacent the free end of each of said arms in fluid communication with said rotor chamber and adapted to be closed by the adjacent free arm end when the adjacent arm is in said outward position and further adapted to permit a charge of combustion gas to expand inwardly against said adjacent Arm and the exposed surface of said rotor and thereby transmit a power impulse to said rotor; exhaust means in fluid communication with said rotor chamber and arranged so that outward movement of said arms and the continued rotation of said rotor force spent charges of combustion gases from the rotor chamber to said exhaust means; means sealing said side portions of said rotor and said arms with respect to said housing end walls; means for selectively transferring gas charges compressed in each compression chamber to said combustion chamber associated with the adjacent arm following in the direction of rotor rotation; and start-up means for initiating the cycle of operation for said arms and said engine; whereby said double-lobe rotor permits each of said arms to complete two cycles of movement between said inward and outward positions for each revolution of said rotor.
 12. A rotary engine in accordance with claim 11 wherein said double-lobe rotor further includes a pair of opposed high dwell segments defined between said first and second segments and adapted to sequentially engage the free ends of a pair of opposed arms to maintain said engaged arms in said outward position for a selected degree of rotor rotation, and a pair of opposed low dwell segments engageable with the free ends of a pair of opposed arms to maintain said engaged arms in said inward position for a selected degree of rotor rotation, and further wherein said rotor segments are arranged so that the inward power impulses transmitted to said rotor by the expansion of combustion gases associated with adjacent pairs of arms are overlapping, and the flow of torque to said rotor and shaft is smooth and continuous.
 13. A rotary engine in accordance with claim 12 wherein said combustion chambers are spherical in configuration to provide said chamber with a low surface-to-volume ratio, and further wherein said high dwell segments of said rotor are adapted to sequentially engage the free ends of said arms and maintain the associated combustion chambers closed after ignition of the combustible charges in the combustion chambers, for a period of between approximately 35 percent and 50 percent of the degrees of rotation through which said rotor engages each arm, so that substantially complete combustion of said charges occurs in said combustion chambers before said rotor releases said free arm ends and permits the charges to expand into said rotor chamber.
 14. A rotary engine in accordance with claim 13 wherein said housing includes a plurality of valve seats in communication with said combustion chambers and wherein the free end of each of said arms includes a valve head for engaging with and sealing against the adjacent valve seat as said high dwell portion of said rotor maintains said arms in said outward positions, to thereby seal the combustion chambers during the combustion of gas charges therein.
 15. The rotary engine in accordance with claim 13 wherein the free end of each of said arms and the inner portions of said housing adjacent said combustion chambers include a plurality of labyrinth grooves which cooperate to seal the combustion chambers from said rotor chamber when said high dwell segments of said rotor maintain said arms in said outward positions.
 16. A rotary internal combustion engine in accordance with claim 11 wherein said arms and double-lobe rotor are adapted to slide transversely within said housing to a condition of equilibrium between said end walls and further wherein said sealing means comprises a plurality of discontinuous labyrinth grooves provided in unaligned arrangement in the side portions of said arms and rotors so as to follow the general contour of the associated arm and rotor, so that said grooves prevent the flow of combustion gases past said arms and rotor.
 17. A rotary internal combustion engine in accordance with claim 11 wherein said exhaust means comprises an exhaust port provided in said housing adjacent each of said armS and a mating valve portion provided on said adjacent arms, with each of said ports being arranged to be closed by said adjacent valving portion when the associated arm is in said outward position and to open into fluid communication with said rotor chamber when said adjacent arm is moved to said inward position.
 18. A rotary internal combustion engine in accordance with claim 17 wherein said exhaust ports are arranged to be opened by the mating valve portions on a pair of opposed arms when the associated arms have engaged with said first portions of said rotor and have swung inwardly through a selected degree of rotor rotation and the adjacent preceding pair of arms is engaged with said low dwell segments on said rotor, so that continued rotation of said rotor engages the preceding pair of arms with said second rotor segments and drives said preceding arms outwardly to force spent combustion gases from said rotor housing through said open exhaust ports.
 19. A rotary internal combustion engine in accordance with claim 12 wherein said first and second segments on said rotor surface are adapted to engage with the free ends of a pair of opposed arms and move said arms inwardly and outwardly, respectively, with substantially simple harmonic motion.
 20. A rotary internal combustion engine in accordance with claim 11 wherein said start-up system comprises: flywheel means secured to said output shaft and defining a circular cam track around said shaft adapted for rotation with said rotor; a cam follower connected to each of said arms and arranged so that said followers are spaced uniformly around such shaft adjacent said cam track; said track including a pair of opposed and symmetrical lift segments engageable with an opposed pair of said followers to drive the connected pair of arms inwardly against said first rotor segment and thereby permit a charge of air-fuel mixture to be drawn into the associated compression chambers by said inwardly moving arms, said cam track further including a pair of opposed and symmetrical release segments adapted to release an opposed pair of cam followers so that said connected pair of arms can be driven outwardly by said second rotor portions to thereby compress the charges drawn into said associated compression chambers; and cranking means for inducing rotation of said flywheel and said rotor to being said cam track segments sequentially into engagement with the cam followers of each of said arms and thereby drive each of said arms through two complete cycles of operation for each revolution of said rotor. 